Biopsy is a medical test involving sampling of cells or tissues for examination. It is the medical removal of tissue from a living subject to determine the presence or extent of a disease. Biopsy is most commonly performed for insight into possible cancerous and inflammatory conditions. It is accurate and reliable. A biopsy device generally includes a needle and a needle tube covering the needle. In use, the needle tube is firstly inserted into the body of the patient to cover the tissue, and then the needle is inserted into the needle tube to a predetermined depth to cut the tissue. The cut tissue is received in the needle tube, and removal from the patient along with the needle tube.
For the above biopsy device, moving of the needle and needle tube are respectively controlled by two actuators and two springs, which is not only complex in structure, but also complex in operation. In addition, a preloading force on the spring is not easy to control.